Extended pinned layer on top of lead/HB to avoid amplitude flipping
View Patent ↗A magnetoresistive sensor having a self pinned structure formed above a free layer and having a pinning stabilization structure to avoid flipping of the magnetic moment of the pinned layer. The pinned layer stabilization structure includes hard magnetic structures formed over the leads in an area outside of the active area of the sensor, and a magnetic layer extends over the active area of the sensor and over the hard magnetic structures outside of the active area of the sensor.
1. A magnetoresistive sensor, comprising:
a sensor stack having a top surface and first and second laterally opposed sides defining a width there between, the sensor stack comprising:
a magnetic free layer;
a non-magnetic spacer layer formed over the free layer; and
a pinned layer formed over the spacer layer;
first and second hard magnetic bias layers extending laterally from the laterally opposed sides of the sensor stack;
first and second leads disposed over the first and second hard magnetic layers respsectively;
a first electrically conductive, non-magnetic lead formed over the first hard magnetic bias layer, the first lead terminating at the sensor stack and extending outward therefrom;
a second electrically conductive, non-magnetic lead formed over the second hard magnetic bias layer, the second lead terminating at the sensor stack and extending outward therefrom;
a third hard magnetic structure formed over the first lead, terminating at the sensor stack and extending laterally outward therefrom;
a fourth hard magnetic structure formed over the second lead, terminating at the sensor stack and extending laterally outward therefrom; and
a stabilizing layer of magnetic material extending across at least a portion of the top of the sensor stack and extending across at least a portion of each of the third and fourth hard magnetic structures.
2. The sensor as in claim 1 , further comprising a capping layer formed over the stabilizing layer.
3. The sensor as in claim 2 . wherein the capping layer comprises Ta.
4. The sensor as in claim 1 , wherein the pined layer comprises:
a first magnetic AP 1 layer;
a first magnetic AP 2 layer;
a first non-magnetic antiparallel coupling layer sandwiched between the
AP 1 layer and the AP 2 layer, the coupling layer being of such a thickness
as to strongly antiparallel couple the AP 1 and AP 2 layers.
5. The sensor as in claim 4 , wherein the first AP 1 layer and the first AP 2 layer each comprise CoFe.
6. The sensor as in claim 4 , wherein the first coupling layer comprises Ru.
7. The sensor as in claim 4 , wherein the first AP 1 layer and the first AP 2 layer each comprise CoFe30.
8. The sensor as in claim 4 , wherein the third hard magnet structure comprises:
a second AP 1 layer;
a second AP 2 layer; and
a second coupling layer disposed between the second AP 1 layer and
second AP 2 layer, the second coupling layer being of such a thickness to antiparallel couple the second AP 1 and second AP 2 layers; and
wherein the fourth hard magnetic structure comprises:
a third AP 1 layer;
a third AP 2 layer; and
a third coupling layer disposed between the third AP 1 layer and the third AP 2 layer, the third coupling layer being of such a thickness to antiparallel couple the third AP 1 and third AP 2 layers.
9. The sensor as in claim 8 , wherein the second AP 1 layer, second AP 2 layer, and third AP 2 layer, each comprise CoFe.
10. The sensor as in claim 8 , wherein the second AP 1 layer, second AP 2 layer, third AP 1 layer, and third AP 2 layer each comprise CoFe, and wherein the second and third coupling layers each comprise Ru.
11. The sensor as in claim 8 , wherein the stabilizing layer comprises CoFe.
12. The sensor as in claim 8 , wherein:
the first AP 1 layer is disposed between the first coupling layer and the stabilizing layer;
the first AP 2 layer is disposed between the first coupling layer; and
the AP 2 layer has a thickness that is substantially equal to a thickness of the AP 1 layer and a thickness of the stabilizing layer combined.
13. The sensor as in claim 1 , wherein the stabilizing layer comprises CoFe.
14. The sensor as in claim 1 , wherein the third and fourth hard magnetic structures each comprise a layer of Cr and a layer of CoPt.
15. The sensor as in claim 1 , wherein:
the third hard magnetic structure comprises a first layer of Cr formed over the first lead; and a first layer of CoPt formed over the first layer of Cr; and
the fourth hard magnetic structure comprises a second layer of Cr formed over the second lead; and a second layer of CoPt formed over the second layer of Cr.
16. The sensor as in claim 15 wherein the stabilization layer CoPt.
17. The sensor as in claim 16 wherein:
the first and second layers of Cr have a thickness of 10 to 20 Angstroms:
the first and second layers of CoPt of the third and fourth hard magnetic structures each have a thickness of about 30 Angstroms; and
the stabilization layer has a thickness of 10 to 20 Angstroms.
18. The sensor as in claim 16 , wherein the pinned layer comprises:
a magnetic AP 1 layer;
a magnetic AP 2 layer; and
a non-magnetic, electrically conductive coupling layer disposed between the AP 1 layer and the AP 2 layer, the coupling layer being of such a thickness as to antiparallel couple the AP 1 and AP 2 layers.
19. The sensor as in claim 18 , wherein:
the AP 1 layer is disposed between the coupling layer and the stabilization layer,
the AP 2 layer is disposed between the coupling layer and the spacer layer; and
the AP 2 layer has a thickness that is substantially equal to the sum of a thickness of the AP 1 layer and a thickness of the stabilization layer.
20. The sensor as in claim 19 , wherein the AP 1 layer and the AP 2 layer each comprise CoFe.
21. The sensor as in claim 1 , wherein an area located between the first and second leads defines an active area the third and fourth hard magnetic structures are disposed outside of the active area.
22. A magnetic recording system, comprising:
a magnetic medium;
an actuator;
a slider connected with the actuator for movement adjacent to the magnetic medium; and
A magnetoresistive sensor, comprising:
a sensor stack having a top surface and first and second laterally opposed sides defining a width there between, the sensor stack comprising:
a magnetic free layer;
a non-magnetic spacer layer formed over the free layer; and
a pinned layer formed over the spacer layer;
first and second hard magnetic bias layers extending laterally from the laterally opposed sides of the sensor stack;
first and second leads disposed over the first and second hard magnetic layers respsectively;
a first electrically conductive, non-magnetic lead formed over the first hard magnetic bias layer, the first lead terminating at the sensor stack and extending outward therefrom;
a second electrically conductive, non-magnetic lead formed over the second hard magnetic bias layer, the second lead terminating at the sensor stack and extending outward therefrom;
a third hard magnetic structure formed over the first lead, terminating at the sensor stack and extending laterally outward therefrom;
a fourth hard magnetic structure formed over the second lead, terminating at the sensor stack and extending laterally outward therefrom; and
stabilizing layer of magnetic material extending across at least a portion of the top of the sensor stack and extending across at least a portion of each of the third and fourth hard magnetic structures.